1. Field of the Invention
The present invention relates to a lighting device including a light-emitting element, and relates to a lighting device including a light-emitting element and a metal plate to which the light-emitting element is thermally connected.
2. Description of the Related Art
There is a lighting device including an alumina-layer-coated aluminum plate, on which a light-emitting element is mounted (For example, see FIGS. 3 and 4 of Japanese Patent Application Laid-Open No. Sho. 59-9982).
Furthermore, there is a lighting device including a ceramic-ink coated aluminum substrate (For example, see Japanese Patent Application Laid-Open No. 2011-151248).
The above-mentioned alumina layer or the ceramic ink layer entirely layered on a surface of a metal plate. When metal plates of the above-mentioned lighting devices are divided from a metal plate assembly with an alumina layer or a ceramic ink layer entirely layered on a surface of the metal plate assembly, there may be liable to crack at the alumina layer or at the ceramic ink in a dividing or dicing step of the metal plate assembly. If there is a crack at an alumina layer or at a ceramic ink layer layered on a metal plate, an electrical insulation may deteriorate.